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Vitamin D successful as an adjunct treatment to preeclampsia medication

Posted on: December 22, 2017   by  Riley Peterson & John Cannell, MD.


Pregnancy can be an exciting and scary time in any woman’s life. However, during these months, not only is the soon-to-be mother responsible for her own health and wellbeing, but now someone else’s. And when one’s health is being threatened by gestational diabetes, preeclampsia or other adverse effects common in pregnancy, this usually happy time can quickly turn into something much more uncertain.

Preeclampsia is the most common condition experienced by pregnant women, and is characterized by high blood pressure and protein in the urine. It is one of the leading causes of maternal and infant mortality. Preeclampsia is usually treated with hypertensive medication. Additionally, doctors will likely try and induce birth as soon as possible, as preeclampsia usually affects the amount of oxygen delivered to the placenta and delivery is the definitive treatment.

Vitamin D status has been associated with preeclampsia risk as well as multiple adverse pregnancy outcomes, according to past research. In an effort to validate past research findings, researchers recently conducted a clinical study explore this relationship further.

This RCT evaluated the effect of vitamin D supplementation as an adjunct treatment for pregnant women with preeclampsia. Researchers included a total of 602 women pregnant who were diagnosed with preeclampsia in their first pregnancy. The women were randomly assigned to one of two groups: the first group was treated with oral nifedipine, a common antihypertensive drug used to treat preeclampsia, and 200 IU vitamin D3/dose (n=298), while the second group was treated with oral nifedipine and a placebo (n=304).

Both groups were given their treatment once every 15 minutes, up to four doses, until their blood pressure reached 150/100 mmHg or lower. The number of doses per individual was recorded for analysis, as was the time after reaching this blood pressure and prior to experiencing another hypertensive episode. Additionally, anthropometrics and adverse side effects were recorded.

This is what the researchers found:

  • Any variation of anthropometric or clinical values between groups was not significant.
  • In group 1, the average time spent attempting to control blood pressure was 8 + 18.3 minutes while group 2 had an average time of 61.1 + 15.9 minutes (p = 0.013).
  • The average time until occurrence of another hypertensive episode in group 1 was significantly longer than group 2 (8.1 +2 hours versus 4.8 + 2.6 hours p = 0.017).
  • Group 1 required significantly fewer doses of nifedipine compared to group 2 (p < 0.05).

This is what the researchers concluded:

“In summary, our data from the current randomized, double-blinded and placebo-controlled clinical trial is the first report on the potency and safety of VD serving as a potential adjuvant to oral nifedipine to enhance the efficacy of therapies against hypertension in women with preeclampsia.”

There were several limitations of this study that should be addressed. First, the researchers did not measure vitamin D status at baseline, which would have been important to know when comparing the similarity of the group characteristics. Additionally, a very small dose of vitamin D was administered and only in one point in time. It seems unlikely that such a small dose at one time would have such an impactful effect as an adjunct treatment. However, there is some discussion about alternate canonical theories that explain the immediate and localized effects of vitamin D supplementation. Check out a blog written by Dr. Cannell a few years back which explains these findings.

The research seems to indicate a beneficial effect of vitamin D supplementation on preeclampsia in pregnant women. Therefore, because it is a safe, effective and inexpensive method of improving one’s health, the Vitamin D Council recommends pregnant women supplement with between 5,000-10,000 IU of vitamin D3 daily.

Have you had an experience with vitamin D and preeclampsia and supplementation that you might want to share? Email us at [email protected].


Peterson, R. & Cannell, JJ. Vitamin D successful as an adjunct treatment to preeclampsia medication therapy. The Vitamin D Council Blog & Newsletter, 2017.


Shi, D.D. et al. Vitamin D Enhances Efficacy of Oral Nifedipine in Treating Preeclampsia with Severe Features: A Double Blinded, Placebo-Controlled and Randomized Clinical Trial. Obstetric and Pediatric Pharmacology, 2017.

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